Purification of paraffin wax



Patented Nov. 21-, 1933 UNITED STATES 1,938,453 PURIFICATION OF PARAFFINWAX Hans Klein, Mannheim, Zorn, Rhine, Germany, asslgnors and HermannHans Kuhler, Oppau, Ludw'lzshalen-on-theto I. G. FarbenindustrieAlrtiengesellschait, FrankIort-on-the- Main, Germany No Drawing.Application January 5, 1931,'Serlal Germany No. 506,740, and in 5Claims.

The present invention relates to the purification or separation ofmixtures of fatty or mineral oils or distillation or destructivehydrogenation products of coal and the like especially of n carbonaceousmaterials containing substantial amounts of paraffin wax. For thepurification or separation of mixtures of fatty or mineral oils ordistillation or hydrogenation productsof coals or other carbonaceousmaterials solvents consisting substantially of a tomato 0! the loweralcohols oi the fatty series or mixtures of several formates havealready been employed.

It has been further found that in the recovery of parailin wax frommaterials containing, substantial amounts thereoi together with othercarbonaceous substances, such as mineral oils and the like, for examplefrom distillation or hydrogenation products of carbonaceous materials,such as coal, or from crude parafiin waxes with the aid oi iormates oflower alcohols, the psreifin was obtained is sometimes not quitecolourless, because the solvent power of these esters for asphalticbodies, such as asphalt and other coloured or colouring constituents orasphalthodies having a lower molecular weight than asphalt and which maybe distilled, but which condense after some time with the formation ofsubstances similar to asphalt, is not always suiticient wholly toprevent the precipitation of these substances on the paraffin wax to beseparated.

We have now found that the said objection is obviated by employing themixtures oi the said ioruiates with organic solvents, the sol vent poweroi which for the said asnhaltic bodies is than that oi the iormates, asfor ex ample mixtures oi the said iormate with benzene, icenaine, carbondisulphide, carbon tetra= chloride and the like. Usually it is onlynecesto add small amounts of these solvents, so for example irom ii to20 per cent reckoned on the amount oi the nurilyinc mixture employed, inorder to improve the quality oi the paraiiln The solvent power of thesaid mixtures ior very small even when employ- .15 oennne- .116 solventmixtures may also be employed for t e purification of fatty or mineraloils, as r ":ainnle soy been oil.

' I .proeess he carried out hy ed the solvent n rtures to the product tohe puri- T ie contaminating substances pass into us may thenbe senaratedfrom the product, as ior example the or the pure oil. in the case ofye-:3, the latter su Jan!!! 17,

sequently washed with the same mixture and the solvent recovered fromthe filtrate by distillation.

Crude paraflin wax from any source may be purified in an advantageousmanner by the process according to the present invention. when stirringthe same with the solvent mixture it is preferably warmed, but goodresults are also obtained at room temperature. The treatment may also becarried out at temperatures above 65 the temperature at which thesolvent ure commences to boil provided a closed vessel is used. The saidsolvent mixture may also con tain more than two components, inparticular it may be used in conjunction with the solvents l0hithertousually employed lor this pse, ior example benzine, benzene,toluene, xylene, carbon disulphide, carbon tetrachloride, trichloroethylene or pyridine. Thus for example a ture of so per cent by volumeof methyl tomato, till 15 per cent of benzene and 5 per cent of methanolgives very good results. In many cases it is preierable to carry out thetreatment oi the masses containing paramn in stages, solvent mixtures oithe said kind, if desired oi difierent composition or differentconcentration, being used in the single stages. Diflerent solvents whichonly consist of the one component may also be used one after anotheniorexample tree. ment with a lei-mate of a. lower alcohol con 6 stitutingthe first stage followed by extraction of colouring matter by treatmentwith a small quail tity of a solvent having a higher solvent power lorthe said colouring matter.

The following examples will the nature of this invention, is notrestricted to these examples. are by weight.

iurther illustrate hut the invention The parts Example 22 Example .2product irons the destructive ny onsentition 01- brown coal lowtemperature carbonization tar consisting of paramn wax and oil iscentrifuged. Hie residual impure parafiln wax flakes are washed with amixtureoi' 80 per cent by volume of methyl i'ormaie and 20 per cent byvolume oi benzene. The paramn wax obtained is pure white in colour.

Example 3 135 parts of a filtrate obtained'by filtration in a press at 0C. of a destructive hydrogenation product of brown coal low temperaturecarbonization tar are boiled for 15 minuies under a reflux solvent isremoved in a filter-press and the residue is washed three times withparis or the same solvent mixture each time. 128 parts of a white paramnwax are obtained which is so pure that it may be supplied for catalyticoxidation with air without further treatment. 4

The filtrate is evaporated and yields a yellowbrown residue (7.5 parts).

What we claim is:

v 1. A process for the purification oi precipitated etude paramn wax bythe removal 01' impurities comprising oils and colored asphalticlikebodies w ch comprises washing said wax with a mixtire of a i'ormate of alower alcohol of the fa'ty series and an organic solvent which has agreater solvent power for asphaitic bodies than said iormate selectedfrom the class consisting 01' e. toluene, xylene, benzine, pyridine,tri-' an undissolved white wax.

2. A process for the purification oi precipitated crude Daramn wax bythe removal of impurities comprising oils comprising oils organicsubsiance is and colored asphalticlike bodies which comprises washingsaid wax with a or a i'orma e or a lower alcohol 01' the fatty seriesand an organic solvent having a greater solvent power for asphalticbodies than the said i'ormate purities from the wax to thereby producean undissolved white wax.

3. A process for the purification of precipitated crude paramn wax bythe removal of impurities and colored asphalticlike bodies i'atty seriesand an organic substance which has a greater solvent power for asphalticbodies than said tormate selected from the class consisting of benzene,toluene, xylene, benzine, pyridine, trichlorethylene, carbon disulphideand carbon tetrachloride and causing said solvent mixture to eil'ectdissolution oi the impurities in said wax by heating the resultingreaction mixture to a temperaiure at which no material dissolution ofwax takes place to thereby produce anundissolved white wax. I

4. A process for refining precipitated crude paraflin wax bythe removalof impurities com to dissolve said imprising oils and coloredasphalticlike bodies which comprises washing said wax with a mixtureconsisting of about per cent by volume of methyl formate, 15 per cent ofbenzene and 5 per cent of methyl alcohol, said benzene and methylalcohol having a greater solvent power for asphaltic bodies than saidiormate,-and causing the said mixture to dissolve the impurities iromthe wax to thereby poduce an undissolved white wax.

5. A process as defined in claim 3 wherein said present in amounts 01'from 2 01- the solvent mixture.

HANS KLEIN. HANS HERMAN}: ZOBN.

to 20 per cent

